A tire loader is described in European patent application 3,418 based on U.S. patent application Ser. No. 872,421 filed Jan. 16, 1978 by A. P. Singh and published Aug. 6, 1979 which is used to pick up and position a tire in a tire press. This device has a support centered on an axis and provided with a plurality of angularly equispaced and radially extending guides carrying respective bead-engaging shoes that can slide radially of the support on these guides. A plate pivoted on the support at the axis is connected at inner pivots to the inner ends of a plurality of angularly equispaced links whose outer ends are pivoted on the respective shoes. A fluid-powered actuator is connected beteween the plate and the support to pivot the plate on the support about the axis. As the inner pivots are moved into a position aligned radially between the outer link ends and the axis, that is in a position with the links extending more radially than tangentially, the shoes move synchronously outward and as the links are moved out of the radial position the shoes move inward.
This type of arrangement, as well as similar equipment described in U.S. Pat. No. 3,167,810, 3,380,115, and 3,564,649 of Soderquist and U.S. Pat. No. 3,845,979 Schatz et al, serves to pick up a tire to be cured or otherwise acted on in a tire press by engaging its upper bead radially outward. This allows the tire core or carcass to be suspended accurately in the tire machine in the desired horizontal position, that is with the tire axis vertical and the tire lying generally in a horizontal plane.
The main problem with such a machine is that it requires constant first-class maintenance to keep it working properly. If any one shoe sticks and does not move prefectly synchronously the core will not be centered in the curing press and the resultant finished tire will be defective. Since the vulcanizing and curing machines operate hot, it is difficult to keep the tire loader working smoothly due to the problems of thermal expansion and constraction and drying-up of lubricants.